This invention relates to a catalytic process for paraffin-isomerization producing branched paraffins under strong acid catalyzed conditions in the presence of aminoalkyladamantanes as hydride transfer catalysts.
Alkylation or isomerization of paraffins under strong acid conditions are well-known processes for producing a wide variety of useful hydrocarbon materials and particularly; gasoline additives. For example, 2,2,4-trimethylpentane is a common blending agent used for gasoline octane improvement which can be produced by alkylating isobutylene with isobutane in sulfuric acid or liquid HF.
An example of an acid-catalyzed reaction process is described in U.S. Pat. No. 3,231,633.
Hydrocarbon conversion processes employing novel Lewis acid systems are disclosed in U.S. Pat. No. 4,229,611 and U.S. Pat. No. 4,162,233, both assigned to Exxon Research and Engineering Company.
U.S. Pat. No. 3,671,598 describes a process for isomerizing saturated cyclic hydrocarbons under strong acid conditions in the presence of an adamantane hydrocarbon. However, no suggestion is made that other specifically substituted adamantanes, particularly those with aminoalkyl substituents, might be more effective in increasing the rate of isomerization of paraffins to branched isomers.
New methods for producing such branched paraffinic hydrocarbons are constantly being searched for in an effort to improve isomerization efficiency. More active catalysts enable these rearrangements to be conducted at lower temperatures where thermodynamic equilibria are more favorable to branched structures, an important factor in butane, pentane and hexane isomerization.